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PRINCIPLES OF VETERINARY SCIENCE 



ment consists in dipping in the regulation sheep dip or kerosene 

 emulsion immediately after shearing. 



ARACHNIDS 



The mange mite of the horse causes the very contagious 

 disease known as mange or itch. This parasite, like all arachnids, 

 is so minute that it is just visible to the naked eye, and possesses 

 four pairs of legs. There are three genera of mange mites recog- 

 nized as infesting the horse — viz., Sarcoptes, Psoroptes, and 



Fia. 84. — The sarcoptic mange mite of the horse. This mite burrows into the 

 deep layers of the skin. (U. S. Department of Agriculture.) 



Symbiotes. Of these, the Sarcoptic mite is the most destructive 

 (Fig. 84) . It burrows tunnels or galleries into the skin. 



The symptoms of mange are intense itching, continuous 

 rubbing, and the formation of scabs along the back and withers, 

 where the parasites lodge just beyond the reach of the mouth and 

 tail of the host. The irritation seems to be most marked during 

 hot nights. The hair drops out and the skin thickens, cracks, 

 and assumes a dead appearance. 



To diagnose mange, scrapings should be made from the skin 



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